Franck 1925 / Condon 1928: vertical electronic transitions favored due to fast-electron / slow-nucleus separation; transition-intensity ~ overlap integral |<chi_v'|chi_v>|^2; explains vibrational progression.
Franck 1925 / Condon 1928: vertical electronic transitions favored due to fast-electron / slow-nucleus separation; transition-intensity ~ overlap integral |<chi_v'|chi_v>|^2; explains vibrational progression.